[Theme] sunlust theme does not work for JSON or YAML diagram/data

[The-Lum]

Hello PlantUML team, (and @theavege),

Describe the bug
During theme galery tests, I discovered this issue:

• this sunlust theme does not work for JSON or YAML diagram/data [Probably due to some JSON conf. tables on this theme]

Tests and Screenshots

• JSON

@startjson
!theme sunlust
{
   "fruit":"Apple",
   "size": "Large",
   "color": ["Red", "Green"]
}
@endjson

• YAML

@startyaml
!theme sunlust
fruit: Apple
size: Large
color:
 - Red
 - Green
@endyaml

PlantUML version

• Tested on version 1.2024.4

Additional context
[Origin Ref. or History of this theme: #1677, #1681, #1691]

[The-Lum]

Fixed by #1727.